1. Field of the Invention
This invention is directed to brake systems used generally in vehicles. In particular, this invention is directed to disc pad brake systems for lowering the audio output of a braking operation. Still further, this invention pertains to a disc pad brake system where a resilient pad member is inserted between an operating longitudinally displaceably piston and at least one carrier plate member within a caliper assembly. More in particular, this invention relates to a disc pad brake system which includes a resilient pad member formed of substantially fluorine substituted alkyl polymer and in particular, poly-hexfluoroethylene. Still further, this invention relates to a disc pad brake system where the resilient pad member is partially secured to a respective carrier plate member and has a dome-shaped portion partially insertable within a bore of an actuating piston. Further, this invention relates to a disc pad brake system utilizing a resilient insert damper member mounted in a loosely fit manner within the bore of a longitudinally actuated piston member.
2. Prior Art
Systems for reducing braking noises are well-known in the art. Numerous prior art systems direct themselves to systems for reducing brake squeal which has been found to be objectionable. However, in general, such prior art systems have not provided a comprehensive brake squeal eliminator system.
The best prior art known to Applicants include U.S. Pat. Nos. 3,566,995; 4,230,207; 4,064,975; 4,022,302; 4,154,322; 4,373,615; 4,240,530; 3,378,116; 4,103,761; 3,966,026; 3,162,271; 3,490,563; 3,498,423; 3,460,652; 4,527,668; 4,485,898; and, 3,848,708.
U.S. Pat. No. 4,022,302 is directed to disc brake pads for the purpose of eliminating braking vibrations and to eliminate brake squeal. In this reference, a layer of latex is used to reduce brake noise and eliminate brake squeal, however, after repeated braking operations, the piston member acting on the latex coating wears through the latex coating and there is a re-establishment of the brake squeal. Additionally, this prior art system is directed to an entire pad assembly that would require the replacement of the pad in place of the existing pad when the latex coating is worn away.
U.S. Pat. No. 3,378,116 is directed to friction pads for disc brakes and in particular is directed to a vibration damping element system. However, this system includes a backing plate which is provided with a recess containing a disc vibration damping material inserted therein. Thus, when the brake pad is worn out, a replacement of the entire pad must be made which increases the cost as well as time for installation.
U.S. Pat. No. 4,154,322 is directed to a squeal preventing disc brake pad assembly which uses a wire mesh screen sandwiched between a backing plate and a shim for contact by a brake piston. However, by the mere composition of the wire mesh screen, such does not permit the releasable locking of a resilient pad member partially within a bore of the actuating piston and requires extensive hardware considerations to mount such a screen in a locking manner to the backing plate.